On Thu, 03 Dec 2015 10:36:18 -0800
"Shi, Yang" <yang.shi@xxxxxxxxxx> wrote:
> > called directly that calls these functions internally and the tracepoint
> > can trap the return value.
>
> This will incur more changes in other subsystems (futex, kvm, etc), I'm
> not sure if it is worth making such changes to get return value.
No, it wouldn't require any changes outside of this.
-long __get_user_pages(..)
+static long __get_user_pages_internal(..)
{
[..]
}
+
+long __get_user_pages(..)
+{
+ long ret;
+ ret = __get_user_pages_internal(..);
+ trace_get_user_pages(.., ret)
+}
>
> > I can probably make function_graph tracer give return values, although
> > it will give a return value for void functions as well. And it may give
> > long long returns for int returns that may have bogus data in the
> > higher bits.
>
> If the return value requirement is not limited to gup, the approach
> sounds more reasonable.
>
Others have asked about it. Maybe I should do it.
-- Steve
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